from what i remember the chain make them reduce to before they became a hunter and Sayoung was a very sick child due to entering a poisonous gate and was basically like a sick victorian child and almost died before awakening so he's gonna end up like that in the next couple chapters but once theyre removed he'll be fine again

They do meet at the wedding and im pretty sure the ML knows its him, MC doesnt know its him but believes it is him and he figures it out pretty quickly